Posted
by
CmdrTaco
on Wednesday May 26, 2010 @09:30AM
from the xanthir-has-almost-70k-hp dept.

EmagGeek writes "University researchers have created a transistor by replacing just seven atoms of silicon with phosphorous. The seven-atom transistor has hopeful implications for the future of quantum cryptography, nuclear and weather modeling, and other applications. 'The significance of this achievement is that we are not just moving atoms around or looking at them through a microscope,' says Professor Michelle Simmons, a co-author of a paper on the subject that is being published by Nature Nanotechnology. The paper is entitled 'Spectroscopy of Few-Electron Single-Crystal Silicon Quantum Dots'."

It sounds like they did this by moving single atoms at a time, and not through any kind of lithography, or mass-producible process. So while neat, like the single atom transistor story from a while back, it doesn't look like they really have a way to produce billions of these at a time. We may have to wait a long time before we see anything like this in our home PCs.

The argument isn't that a quantum computer isn't necessary. It's pointing out the fact that computing is often I/O limited - how fast a computer can move data around to be processed. He's saying that advances need to come in other areas before things like this are significant.

And, as someone with a background in these things - you don't make a good transistor with 7 phosphorus atoms. There has to be more to it. The fact that they create

It'll take a really wicked manufacturing process to ever make, too. 7 atoms? What if you get only 6? What if you get 8? What if one is slightly off position? We've already been at sub-100nM processes for years now, and things are already too "grainy" for real comfort.

Oh yeah, what's the difference between "on" current and "off" current?

Yes, even in a crystalline structure. Diffusion in solids at the macroscopic scale seems slow compared to say, cream in your coffee, but at the atomic scale... They did this at the surface, which makes it even worse. I can't imagine this lasting any useful amount of time without some SEVERE cooling measures. I'm not sure if even liquid nitrogen could save it. IAAMS.

I'm not involved directly in any research using quantum dots/wells, so I don't feel I qualified to make that kind of prediction. However, the article shows the quantum dot the transistor was contained in, which looks like its an order of magnitude larger (70-80 atoms). It's one or two atoms out of 70 move, there isn't going to be nearly the change in properties compared to one or two in the seven that act as the gate. Computer components need to be able to last for years at or near room temperature, and

It'll take a really wicked manufacturing process to ever make, too. 7 atoms? What if you get only 6? What if you get 8? What if one is slightly off position?

Building a car with 4 wheels? What if you only get 3? What if you get 5? What if one is slightly off position?

An automated process doesn't care about size. What they did, can be replicated. Thus, it can be automated, unless there's a creative process involved that implies the use of a human mind, which I strongly doubt.

If the automation is too slow, it can be multiplied. If multiplying is still not enough, the process itself of creating and assembling multiple automatons can be multiplied.

It'll take a really wicked manufacturing process to ever make, too. 7 atoms? What if you get only 6? What if you get 8? What if one is slightly off position?

Building a car with 4 wheels? What if you only get 3? What if you get 5? What if one is slightly off position?

An automated process doesn't care about size. What they did, can be replicated. Thus, it can be automated, unless there's a creative process involved that implies the use of a human mind, which I strongly doubt.

If the automation is too slow, it can be multiplied. If multiplying is still not enough, the process itself of creating and assembling multiple automatons can be multiplied.

Price vs usefulness of the final product may well be a problem, but size isn't. It was until it was solved, which is precisely the point of the news.

In macroscopic terms the world is simple. The finer the resolution the more complex the world gets. In nanoscopic terms the world is complicated.

Our current technology allows us to automate macroscopic processes with high precision. Nanotechnology however is one leading edge technology, and as such the precision certainly isn't there to make a fair comparison to automated macroscopic processes.

Think of a doctor performing surgery: a large benign tumor in section of fat could be easily removed, while a min

In macroscopic terms the world is simple. The finer the resolution the more complex the world gets. In nanoscopic terms the world is complicated.

Making chips is considerably harder than making bricks; and yet we do make both.

Our current technology allows us to automate macroscopic processes with high precision. Nanotechnology however is one leading edge technology, and as such the precision certainly isn't there to make a fair comparison to automated macroscopic processes.

Making chips was once leading edge technology, not comparable to making bricks; and yet we made both.

Think of a doctor performing surgery: a large benign tumor in section of fat could be easily removed, while a miniscule brain tumor would probably be one of the most difficult to remove.

Removing a minuscule brain tumor is much harder than amputating a leg; and yet we do both.

That's precisely the point of science and technology. Some guy spends years doing something that was previously impossible. Some other guys try little variants on the same action. And then a guy develops a process of doing the exact same thi

The problem is that even at current sizes, we experience a large amount of process variation, which is basically deviation of the actual device sizes from the ones you specified due to it being so damn hard to make something that small:

http://en.wikipedia.org/wiki/Process_variation_%28semiconductor%29

Process variation is becoming one of the biggest problems as chips shrink, because the variation in transistor sizes means that every circuit has to be designed with some amount of safety buffer, which increase

Exactly. That, indeed, is a problem specific to the mechanization of the process.

Additionally to improvements in fabrication techniques and design alterations (which I don't think will be possible in this case) there's also the often used option of discarding the bad results, which, as always, turns into a pure production cost problem.

In macroscopic terms the world is simple. The finer the resolution the more complex the world gets. In nanoscopic terms the world is complicated.

Making chips is considerably harder than making bricks; and yet we do make both.

Our current technology allows us to automate macroscopic processes with high precision. Nanotechnology however is one leading edge technology, and as such the precision certainly isn't there to make a fair comparison to automated macroscopic processes.

Making chips was once leading edge technology, not comparable to making bricks; and yet we made both.

Think of a doctor performing surgery: a large benign tumor in section of fat could be easily removed, while a miniscule brain tumor would probably be one of the most difficult to remove.

Removing a minuscule brain tumor is much harder than amputating a leg; and yet we do both.

That's precisely the point of science and technology. Some guy spends years doing something that was previously impossible. Some other guys try little variants on the same action. And then a guy develops a process of doing the exact same thing but better, faster and cheaper.

Once the action passes through the imposibility barrier, the steps from "breakthough" to "mundane" are well known. We've spent several thousand years walking those steps on each new discovery.

So then, just so I'm clear, leg amputation is just as difficult as brain surgery; bricks are just as hard to make as silicon wafers.

Thanks for clearing all that up. Now that you've enlightened me on now the world works I will fly home after work this evening using nothing but my arms. Because I can walk with my legs.

So then, just so I'm clear, leg amputation is just as difficult as brain surgery; bricks are just as hard to make as silicon wafers.

The point is precisely that being harder doesn't stop us from doing things.

This conversation started with someone pointing the extra difficulties of a new, just proven, process. My point is that those difficulties, that obviously make the problem a hard one, were exactly what was proven resoluble. The news are that those problems were surpassed. We're now on the mechanizing the solution phase.

The point is that the initially mentioned difficulties are the "already solved" ones. Not that it's an easy process

What are you smoking? Reliably being able to produce something so intricate and tiny, on any useful scale, is fantastically more complicated than producing current silicon chips. The process isn't proven - not even close.

There's a big difference between "something that can be done" and "something that can be done for a profit"; the latter having considerably more motivation (and desirability) behind it.
Note that a good case-in-point for your argument is the first transistor made by Bell Labs in 1947. This transistor was large and crude by today's standards, but the fact that it *could* be done made it desirable to pursue the technology.

Just because you can do something many times, doesn't mean it can be automated.

Why you think it is 'solved' is beyond me. Will this turn into a practical application of optical drives? I hope so, but there are a lot of steps and process to be worked on before we can say it's possible to mass produce.

In very simple terms, transistors work like a switch. When a voltage is applied to the base (one terminal), they allow current to flow between the collector and emitter (other two terminals). "On" current is when the transistor is allowing the current to flow. "Off" is...off. No current flows.
If I'm wrong, someone correct me. I'm helping someone on a project with some transistors, and need to know if I'm messing it up.

"Off" is almost never zero current. There's usually just a tiny amount of 'leakage' current, although some quantum designs (such as this one seems to be) can have exactly no current while off.

Basically, while all our computers and data are binary, they operate in an analog environment. We just treat any value greater than (for example) analog 0.8 as a digital 1, and anything less than analog 0.2 as a digital 0. The problem has been as we shrink the gate size and thickness and reduce supply voltage in or

You've got the theory basically correct, but in the real world the "off" current is just less current, not zero current. To get a good signal to noise ratio, you want Ion / Ioff to be as big as possible. In older processes (or thick oxide devices) you can get really good ratios. You could have an Ion of 10mA and an Ioff of 10nA, for example, for a ratio of 1e6. For newer process nodes on thin oxide devices, that ratio may get as low as 1e3 or worse. In that range, the device still works well for digita

But see, that's exactly why I made my remark. I've been watching the characteristics of these "transistors" the process guys give us degrade with each generation. Active current is kept under fairly decent control, but standby current is rising fast. For a silly joke, I like to think of 2 lines on a chart, active and standby currents, and wonder when standby will surpass active.

BTW, in spite of your saying the device isn't suitable for digital circuitry - analog circuitry is a heck of a lot tougher. By

I agree completely and thought it was a good question in your post. I was just trying to give a simple explanation of why you would be interested in Ion vs. Ioff for guppysap13.

Wiring up the device is a whole other issue with this 7-atom gate. The small process nodes already have the total device area dominated by the source/drain just to be able to wire it up. Going to effectively zero gate area will only get you maybe a 10% improvement in total area usage without some major changes in how the circuitry

While I would agree that this is a proof of concept rather than mass production, I don't think we need billions of quantum computers. Does every home PC need to be a quantum computer anyway? The value of a single quantum computer may offset the cost of building it one atom at a time.

They did it using an atomic force microscope (very sharp needle) to make room for the phosphorus atoms on the silicon surface (removing the hydrogen termination in certain places). Phosphene gas PH_3 then places phosphorus atoms in the vacated holes, and finally silicon is grown over the top using a low-temperature CVD process. It's a beautiful technique that took them several years to get right.

We move forward while we move back, if it needs to be in a vacuum then it would use a vacuum tube, while it's good for music it's bad for computers since we moved forward from these to transistors. I'm thoroughly confused now.

It would have to be in a tube to be a vaccuum tube, but it would still be a transistor. The way a vaccuum tube works is electricity heats a filiment (cathode), analogous to a transistor's emitter, which throws out electrons and photons. There is a mesh, analogous to a transistor's gate, that the current to be amplified is fed to which controls controls how much energy reaches the tube's anode. The anode is analogous to a transistor's collector.

It would have to be in a tube to be a vaccuum tube, but it would still be a transistor. The way a vaccuum tube works is electricity heats a filiment (cathode), analogous to a transistor's emitter, which throws out electrons and photons. There is a mesh, analogous to a transistor's gate, that the current to be amplified is fed to which controls controls how much energy reaches the tube's anode. The anode is analogous to a transistor's collector.

Even if this were inside a vaccume tube, it would still be a transistor, while an old-fashioned amplifier tube is not a transistor.

If only there was some way we could enclose the whole active device in some form of vacuum assembly made from, say, a stable material like glass? Maybe we could also create a temperature controlled environment for the unit to ensure consistent operation by including perhaps a heater?

Yes, of course I do, but things change under different conditions, like a chip with an order of magnitude more transistors on it, operating at an order of magnitude faster than before.

I understand how N and P type semiconductors are made, but elements are not always uniform across temperature/pressure ranges - grey tin is a semiconductor below about 12 degrees C, but becomes a metal above that temperature.

At the scales we are talking about. things are not always how they seem.

Current transistors use phosphorous, and it is not a problem. The phosphorous bonds to silicon atoms. But in the long term reactions will still happen. So all current chip dies have "die passivation", where the die is covered with something like silicon dioxide (glass), silicon nitride (ceramic), or maybe other things. It's a very effective hermetic seal.

Would someone tell me how this happened? We were the fucking vanguard of quantum transistors in this country. The University of New South Wales' Centre for Quantum Computer Technology (CQCT) Mach7 was the quantum transistor to own. Then the other guy came out with a seven-atom transistor. Were we scared? Hell, no. Because we hit back with a little thing called the Mach7Turbo. That's seven atoms and an aloe strip. For moisture. But you know what happened next? Shut up, I'm telling you what happened--the bast

Doping really isn't relevent here, since we're not talking CMOS or FET transistors. While it's still a transistor operationally, the structure is completely different, so there is no p- or n-type material, per-se.

What this is, is a quantum dot [wikipedia.org] which acts as a single electron transistor [wikipedia.org]. It's as different from a CMOS transistor as CMOS is from a vaccuum tube. So, asking for a doping ratio of a quantum dot transistor is like asking for the grid spacing of a CMOS, or the oxide thickness of a JFET: it doesn

The headline is (again) inaccurate. It's not a 7-atom transistor, it's a transistor with 7 phosphorus atoms (dopant) inserted into the silicon crystal structure by placing the atoms using a tunneling microscope.

In general [wikipedia.org], it's taken the semiconductor industry 10-20 years to shrink a process by an order of magnitude (e.g. 1995=350nm, 2010=32nm). 11nm isn't really expected until 2022 (that's mass production, not just tech demos which are typically several years ahead). Presumably the 4nm process, which is perhaps still a couple of process sizes smaller than 11nm, would happen some time after that. There are still a lot of hurdles between producing a technology demo in a lab setting and the point where you've dev

Every time I try to solder one of these newfangled transistors to the breadboard, the drop of solder overflows, from the atom I am trying to connect over onto one of the other atoms, and the two atoms converge in a glob of molten solder causing a short circuit. I can never get the glob of solder off of the other atom after that.

The brain does more than just lose cells. Day to day transmission is incredibly noisy, with spurious signaling, suppressive and active signals that are actually quite chaotic, and yet underneath all this in a weird twist of things, transmission appears to be digital, just with absurd amounts of error correction built in.